>> reporter: this embassy suicide bombing happened on hillary clinton's last day as secretary of state. she was informed immediately and made calls all morning before turning her duties over to her replacement, john kerry, who tracked this all day. the blast was destructive and deadly. 1:13 in the afternoon, a lone male wearing a suicide vest beneath his coat walked up to the u.s. embassy. he approached a visitor's entrance -- the first point of access to the embassy nearly 500 feet from the critical main building. several turkish guards were standing post, several more were behind bulletproof glass and steel gates. turkish tv reported that a security camera shows the bomber panicked when a metal detector went off. the turkish guard then shouted to others, "run away, a bomb." and the camera went black as the vest exploded. >> we have very good security to ensure people are stopped before they can actually get inside the fence inside the compound. that is exactly what happened. >> reporter: the turkish guard was killed outright, several others hit by flying debris received minor wounds,